Prevalence of Vertebral Fractures (VF) in Primary Hyperparathyroidism (PHPT)

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: SUN 234-256-Bone & Calcium Metabolism: Clinical Trials & Case Series
Clinical
Sunday, June 16, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board SUN-238
Zahrae Sandouk*1, Maryam Sharifi2 and D. Sudhaker Rao3
1Henry Ford Hospital, Detroit, MI, 2Henry Ford Hospital, 3Henry Ford Hosp, Detroit, MI
Background: The available data on VF in PHPT patients is conflicting. Some studies suggest an increased risk of fractures with a decline after parathyroidectomy (PTX)(1). Others have reported that mild PHPT did not increase fracture risk and was protective of VF(2). Our objective was to determine the prevalence of VF as well as hip and wrist fractures in a large cohort of PHPT patients, which might impact the current BMD T-score guidelines in recommending PTX in asymptomatic patients.

Methods: We reviewed data on VF in patients with PHPT seen from 2004-2011. Patients with renal HPT, scoliosis, and those without imaging studies in electronic medical record (EMR) were excluded. Lateral spine images (from chest and spine x-rays, CT scans) were reviewed and blindly reassessed by an expert radiologist. A >20% reduction of any height (anterior and/or posterior) of vertebra was considered as VF. Hip and wrist fracture data was collected from EMR. We estimated that a sample size of 500 would provide an adequate power in difference from the published reports on VF in women. Descriptive statistics were performed using two-sided two-sample t-test and Fisher's exact test as appropriate.

Results: The 404 of the 500 patients included had mean age of 68.3 ± 11.8y; mostly women (82%) with 55% blacks. Mean serum Ca was 10.8 ± 0.64 mg/dL, Cr 0.96 ± 0.23 mg/dL, and PTH 115 ± 102 pg/m. The prevalence of VF was 9.4% in the total cohort; 10% in black and 8.3% in white women, both lower than in women without PHPT (14%)(3). In white women >65y, VF prevalence was 12.3% (5.8-22.1), lower than in a published control group (19.6%)(4). Women with VF were older (77.6±8.2 Vs 67.5±11.5y; p<0.001) with similar distribution of blacks and whites. The prevalence of wrist and hip fractures was 5.7% and 1.8% respectively, both lower than in the general population. However, none of the differences except for age was significant.

Conclusions: We conclude that VF risk in PHPT patients is not increased. This is the first large study that included blacks and whites, a more representative of the PHPT population in the community. Studies suggesting higher fracture risk almost certainly had some selection bias or included innapropriate control group that may have exagerated the VF risk. Our data also suggests that age is an important determinant of VF not the presence of PHPT. Further studies are needed since BMD T-scores are currently used to recommend PTX without a sound evidence base.

(1) P. Vestergaard, C. L Mollerup, V. Frøkjær et al. BMJ 2000;321:598–602. (2) Wilson RJ, Rao S, Ellis B, Kleerekoper M et al. Ann Intern Med. 1988 Dec 15;109(12):959-62. (3) Elizabeth J Samelson,1,2 Marian T Hannan,1,2 Yuqing Zhang, Harry K Genant et al. J Bone Miner Res 2006;21:1207–1214. (4) Michael C Nevitt, Steven R Cummings, Katie L Stone et al. J Bone Miner Res 2005;20:131–140.

Nothing to Disclose: ZS, MS, DSR

*Please take note of The Endocrine Society's News Embargo Policy at http://www.endo-society.org/endo2013/media.cfm